<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        * {
            padding: 0;
            margin: 0;
            box-sizing: border-box;
        }
        
        .box {
            width: 150px;
            height: 150px;
            margin: auto;
        }
        
        .box1 {
            background-color: brown;
        }
        
        .box2 {
            background-color: pink;
            padding: 10px;
            border: 10px solid black;
            box-sizing: content-box;
        }
        
        .box3 {
            background-color: chartreuse;
            padding: 10px;
            border: 10px solid black;
            box-sizing: border-box;
        }
    </style>
</head>

<body>
    <div class="box box1">正常</div>
    <div class="box box2">标准</div>
    <div class="box box3">怪异</div>
</body>

</html>